The present invention generally relates to a printing method, and more particularly, to a thermal transfer printing method capable of printing high quality images on a plain paper sheet, and printing media to be employed for said method.
In the field of thermal transfer printing, there has been known a dye thermal transfer printing method which is the only printing technique superior in compact size, facilitated maintenance, and instantaneous operation of an apparatus employed therefor, and capable of providing an image at high quality equal to that in color photography. In the dye thermal transfer printing method as referred to above, it is so arranged that a transfer member having a coloring material layer containing a sublimining dye provided on a thin film base, and an image-receptor or image receiver provided with a dyeing layer on a thick film such as a synthetic paper or the like, are overlap each other, and by transferring the subliming dye into the dyeing layer through employment of a thermal recording head, a color mixed image of dye molecules is recorded or printed.
The printing is generally effected by driving the image-receptor, and causing a transfer member to follow the movement through frictional force between the image-receptor and the transfer member.
On the other hand, in order to affix the printed image onto various places, there has also been conventionally proposed a practice which employs tack sheets. In this practice, the image-receptor has a double-sheet structure, and an adhesive material is applied onto a reverse surface of a base material formed with an upper dyeing layer so as to be fixed on a support member provided with a lower parting layer, whereby after the printing, the upper layer is separated or peeled off for being fixed on a post-card, etc. 10 Meanwhile, printing of characters or letters has been effected on a plain paper sheet smoothed on its surface through employment of a molten ink transfer member.
As described above, the printed image by the dye thermal transfer printing method is formed on the specially prepared paper sheet, and therefore, running cost tends to be high, thus preventing said printing technique from spreading widely for general applications.
Moreover, in the recent times of multi-media, information includes images mixed with characters, and despite a strong demand for printing such information on plain paper in a similar manner as in a copying apparatus, it has been impossible to obtain an image of high quality on a plain paper sheet by the conventional dye thermal transfer printing method.